The present invention relates to range or position determination. In particular, position information is used to aim a camera.
Global navigation satellite systems (GNSS) allow a receiver to determine a position from ranging signals received from a plurality of satellites. Different GNSS systems are available or have been proposed, such as the global positioning system (GPS), Galileo, or GLONASS. The GPS has both civilian and military applications. Different ranging signals are used for the two different applications, allowing for different accuracies in position determination.
Position is determined from code and/or carrier phase information. A code division multiple access code is transmitted from each of the satellites of the global positioning system. The spread spectrum code is provided at a 1 MHz modulation rate for civilian applications and a 10 MHz modulation rate for military applications. The code provided on the L1 carrier wave for civilian use is about 300 kilometers long. The codes from different satellites are correlated with replica codes to determine ranges to different satellites. A change in position of the satellites over time allows resolution of carrier phase ambiguity for greater accuracy in position determination.
In addition to satellite-based systems, land-based transmitters may be used for determining a range or position. For example, U.S. Pat. No. 7,339,525 discloses land-based transmitters for determining position in a mining environment. In open pit mines, a diversity of mobile equipment and vehicles interacts with each other on the same roads under various (and sometimes extreme) environmental conditions. The vehicles on the roads in the mine include small personal vehicles, such as pick-ups and sport utility vehicles, all the way to 400 ton capacity Caterpillar 797 haul trucks with over 12 foot diameter tires. The equipment interaction presents many opportunities for collisions and obstructions. To assist in tracking the various vehicles and avoiding problems, the position of each vehicle is determined from signals transmitted from the land-based transmitters or other systems, such GPS, GLONASS, Loran, inertial measurement units or any combination of the above.
A mine may have a single dispatch location, which visually monitors the activity within the pit of the mine. If needed, the dispatch personnel may engage an “All Stop” signal via CB radio to all of the heavy equipment in the mine. In addition, mines have experimented with radar/beacon systems (on the haul trucks), TCAS-like Traffic Collision Avoidance Systems (SafeMine), and others, as well as with autonomous vehicles, or remotely operated vehicles. In case of autonomous or remotely operated vehicles, manual oversight and override functions are maintained for safety purposes. A manual restart is enabled if a safety stop has been triggered by any of the numerous safety systems on board, such as vision systems, proximity radar and others. This requires a visual inspection of the machine from all angles to assure no personnel nor equipment are in the path of the vehicle.
For autonomous vehicles, developers have incorporated on-board cameras, which visually observe areas in front and at the sides of the vehicles. The onboard systems are typically focused on the areas around the vehicle, and not the vehicle itself. A camera system mounted on or near a dispatch center may provide a non-vehicle point of view of the situation. The dispatch-mounted cameras are steered manually or are permanently aligned with a road intersection, providing only a single vantage point. A camera at the dispatch center may not have line-of-sight with a particular vehicle due to obstructions, such as due to a non-circular mine arrangement.